Deep Sleepers – Northern Elephant Seals Sleep Far Under Ocean Floor


A current research into the sleeping habits of northern elephant seals has discovered that the large pinnipeds sleep for simply two hours a day – lower than nearly another mammal – and that sleep takes place deep underwater, the place the seal is protected from predators comparable to sharks and killer whales.

Northern Elephant Seal Sleep Analysis

Researchers from Scripps Establishment of Oceanography and UC Santa Cruz monitored the seals’ diving actions by attaching neoprene caps to the animals’ heads with a detachable adhesive.

Utilizing these and different sensors, the workforce had been capable of monitor quite a few elements of a seal’s dive, together with length, depth and stroke price. Critically to the research, the sensors had been additionally capable of monitor the seal’s sleep state.

Northern Elephant Seals Fighting
Whereas at sea, northern elephant seals sleep for simply 2 hours a day. The species sometimes spends simply two months on land annually.

The researchers then mixed their very own information with present information drawn from over half 1,000,000 northern elephant seal dives compiled by the Costa lab at UC Santa Cruz.


The workforce discovered that the northern elephant seal – whereas at sea* – sleeps for a median of simply 2 hours per day. The one mammal recognized to spend as little time sleeping is the African elephant.

* Elephant seals spend as much as ten months of the yr at sea, solely hauling out to mate, give beginning and molt (see under).

One other attention-grabbing facet of the northern elephant seal’s sleep patterns is that sleep happens far under the floor.

That is presumably an anti-predation adaptation; whereas at or close to the floor, the seals are at their most weak from assaults by sharks and killer whales.

When the seals enter REM sleep, they cease swimming, flip upside-down, and progressively spin downwards. This means that, like ours, the seals’ motion turns into inhibited throughout this section of sleep.

Information comparable to that exposed by the research is essential in constructing a whole image of the northern elephant seal’s conduct, thereby serving to protect the inhabitants of this characterful ocean mammal.

The unique paper could be learn right here (article behind paywall).

Northern Elephant Seal

The northern elephant seal is the second-largest seal species; solely the intently associated southern elephant seal is bigger. Male northern elephant seals can develop as much as 4-5 meters in size and weigh between 1,500 and a couple of,300 kg – that’s considerably heavier than a typical compact automobile.

Northern elephant seals are sometimes discovered within the japanese Pacific Ocean, starting from the Gulf of Alaska all the way down to Baja California in Mexico.

Through the breeding season, the seals migrate to pick rookeries on offshore islands and sure mainland seashores.

A major rookery for the species is the Año Nuevo State Park in California, the place every winter they arrive ashore in giant numbers to mate and provides beginning.

Elephant seals are carnivorous and feed principally in deep ocean waters. Their food regimen is numerous, consisting primarily of fish and squid, however it could additionally embrace sharks and rays.

The seals are recognized to forage at depths of round 300 to 600 meters, however they’re able to diving as much as 1500 meters deep and may stay submerged for greater than an hour, making them one of many deepest diving pinnipeds.

How Lengthy Do Northern Elephant Seals Spend At Sea?

Northern elephant seals spend nearly all of their life at sea, endeavor two prolonged open-ocean voyages annually between their breeding and molting intervals on land.

After the breeding season, they continue to be at sea for a median of 2-3 months earlier than returning to shore for molting.

Following this, they embark on an extended post-molting migration that lasts 7-8 months for females and 4-5 months for males.

Women and men spend 80% and 90% of their lives within the ocean, respectively. This makes them some of the aquatic of all pinniped species, spending as much as 10 months of the yr within the ocean and demonstrating a rare capability for diving and long-distance migration.

Uncover Extra With Energetic Wild

Foremost animals web page: Animals

Uncover extra concerning the southern elephant seal: Southern Elephant Seal

Uncover extra ocean animals: Ocean Animals


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